1. Field of the Invention
The present invention relates to a cleaning blade member and, more particularly, to a cleaning blade member for removing a toner deposited on a toner image carrier employed in an electrophotographic process-such as a photoconductor or a transfer belt, on which a toner image is formed and which transfers the formed image to an image receptor.
2. Background Art
Generally, in an electrophotographic process, electrophotographic apparatus parts such as an electrophotographic photoreceptor and a transfer belt are used cyclically and repeatedly, and a toner deposited thereon is removed by means of a cleaning blade. Japanese Patent Application Laid-Open (kokai) No. 2003-302802 discloses that members for use in such a cleaning blade are made of polyurethane. Polyurethane is employed because it has excellent wear resistance, exhibits sufficient mechanical strength without incorporating additives such as a reinforcing agent thereinto, and does not stain objects. When a cleaning blade has excessively high friction coefficient, contact between the cleaning blade and an object such as a photoconductor becomes unfavorable. Thus, a variety of measures have been taken for reducing friction coefficient, such as an approach in which a lubricating component is applied to the cleaning blade tip to come into contact with an object; an approach in which a lubricating component is added to polyurethane; an approach in which a lubricating component is incorporated into polyurethane through copolymerization; and an approach in which a lubricating coating material is applied to a polyurethane blade member.
However, these approaches have drawbacks. For example, the approach of applying a lubricating component cannot provide a long-term lubrication effect. When the approach of adding a lubricating component is employed, difficulty is encountered in bonding a blade member to a substrate member, and problematic bleeding of the additive occurs, resulting in staining objects. When a lubricating component is copolymerized with polyurethane, the formed polymer material comes to have unsatisfactory characteristics, resulting in reduced wear resistance and staining of an object by a low-molecular-weight component. In addition, since factors controlling friction coefficient have not been completely elucidated, designing of suitable cleaning blades is difficult.
The present inventors have carried out extensive studies in order to solve the aforementioned problems, and have found that friction coefficient depends on the ratio of Young's modulus to rebound resilience. The present invention has been accomplished on the basis of this finding. Notably, Japanese Patent Application Laid-Open (kokai) No. 2003-302802 discloses a blade member whose physical properties, including Young's modulus and rebound resilience, fall within specific ranges. However, this document does not teach the relationship between friction coefficient and these physical properties.